Ecdysteroids are a steroid hormone responsible for the regulation of molting of an insect, and it has been first discovered by Butenanadt and Karlson in 1954. After that, in 1996, ecdysteroids were firstly identified in plant by NaKanishi and Koreeda. Ecdysteroids are one group of 2,3,14-trihydroxy-Δ-7-ketosteroids, and they are the compound belonging to polyhydroxylated steroids including known ecdysterons and ecdysones or the like. Although their activity in plant is not fully known, plant ecdysteroids are known to exhibit an influence on a plant defense mechanism as they show an effect of inhibiting feeding, avoidance, and insecticidal activity against some non-adapted phytophagous insects.
Meanwhile, cytochrome P450 (CYP) is contained in various plants, and as an enzyme having heme structure, it is found not only in a plant but also in microbes, molds, and mammals. In particular, many family types of cytochrome P450 gene are found in several plants in which it constitutes almost 1% of the whole genome. Also in Arabidopsis thaliana, 246 cytochrome P450 genes and 26 pseudo cytochrome P450 are identified and reported. In plant, they are known to be involved with a biosynthetic reaction of a plant hormone or play a role of a signal transducing molecule or an element of a defensive reaction. It is also known to be involved with a biosynthetic pathway of a natural plant material like phenylpropanoids, alkaloids, terpenoids, lipids, cyanogenic glycosides, and glucosinolates as well as auxins, gibberellins, jasmonic acid, and brassinosteroids that are known as a plant growth regulator. In particular, cytochrome P450 exhibits an enhanced expression in response to a stimulation form outside like attacks by molds, microbes, insects, or mammals, and the enhanced expression leads to synthesis of materials that are related to a defensive reaction of a plant. Based on these facts, it is expected that cytochrome P450 can be used, together with a study and understanding of related genes and a signal transduction system, for development of a bioengineered plant with increased resistance to harmful insects or, as a plant genetic material having resistance to harmful insects, it can be practically used for molecular breeding or the like.
Meanwhile, in Korean Patent Registration No. 0834380, “Cytochrome P450 gene for enhancing water resistance of plant by using CYP78A7 derived from Arabidopsis thaliana” is disclosed, and in Korean Patent Registration No. 1256277, “Cytochrome P450 gene (CaCYP450A) from pepper which is involved with resistance reaction against pathogen and disease-resistant transgenic plant using the same” is disclosed. However, there is no description related to the method for producing a transgenic plant with increased content of 20-hydroxyecdysone using CYP85 gene from Spinacia oleracea and a plant produced by the production method as described in the present invention.